what weeks do you visit ob?

Julie
My schedule got all messed up! I went at 8weeks, 12 weeks and was SUPPOSED to go at 16. However I made an appointment because I thought I had an infection at 14 weeks and they asked me to change my next one to 18 weeks I'm assuming because I was seen then. So now I'm going 18 weeks, 22 weeks, 26 weeks etc. 
Does it matter when I go? I just always thought it was a straight 8,12,16,20 etc.